Hybrid maize plant and seed (35R57)

ABSTRACT

According to the invention, there is provided a hybrid maize plant, designated as 35R57, produced by crossing two Pioneer Hi-Bred International, Inc. proprietary inbred maize lines. This invention relates to the hybrid seed 35R57, the hybrid plant produced from the seed, and variants, mutants, and trivial modifications of hybrid 35R57.

FIELD OF THE INVENTION

This invention is in the field of maize breeding, specifically relating to a hybrid maize line designated 35R57.

BACKGROUND OF THE INVENTION Plant Breeding

Field crops are bred through techniques that take advantage of the plant's method of pollination. A plant is self-pollinated if pollen from one flower is transferred to the same or another flower of the same plant. A plant is cross-pollinated if the pollen comes from a flower on a different plant.

Plants that have been self-pollinated and selected for type for many generations become homozygous at almost all gene loci and produce a uniform population of true breeding progeny. A cross between two different homozygous lines produces a uniform population of hybrid plants that may be heterozygous for many gene loci. A cross of two plants each heterozygous at a number of gene loci will produce a population of hybrid plants that differ genetically and will not be uniform.

Maize (Zea mays L.), often referred to as corn in the United States, can be bred by both self-pollination and cross-pollination techniques. Maize has separate male and female flowers on the same plant, located on the tassel and the ear, respectively. Natural pollination occurs in maize when wind blows pollen from the tassels to the silks that protrude from the tops of the ears.

The development of a hybrid maize variety involves three steps: (1) the selection of plants from various germplasm pools for initial breeding crosses; (2) the selfing of the selected plants from the breeding crosses for several generations to produce a series of inbred lines, which, although different from each other, breed true and are highly uniform; and (3) crossing the selected inbred lines with unrelated inbred lines to produce the hybrid progeny (F1). During the inbreeding process in maize, the vigor of the lines decreases. Vigor is restored when two different inbred lines are crossed to produce the hybrid progeny (F1). An important consequence of the homozygosity and homogeneity of the inbred lines is that the hybrid created by crossing a defined pair of inbreds will always be the same. Once the inbreds that create a superior hybrid have been identified, a continual supply of the hybrid seed can be produced using these inbred parents and the hybrid corn plants can then be generated from this hybrid seed supply.

Large scale commercial maize hybrid production, as it is practiced today, requires the use of some form of male sterility system which controls or inactivates male fertility. A reliable method of controlling male fertility in plants also offers the opportunity for improved plant breeding. This is especially true for development of maize hybrids, which relies upon some sort of male sterility system. There are several options for controlling male fertility available to breeders, such as: manual or mechanical emasculation (or detasseling), cytoplasmic male sterility, genetic male sterility, gametocides and the like.

Hybrid maize seed is typically produced by a male sterility system incorporating manual or mechanical detasseling. Alternate strips of two inbred varieties of maize are planted in a field, and the pollen-bearing tassels are removed from one of the inbreds (female) prior to pollen shed. Providing that there is sufficient isolation from sources of foreign maize pollen, the ears of the detasseled inbred will be fertilized only from the other inbred (male), and the resulting seed is therefore hybrid and will form hybrid plants.

The laborious, and occasionally unreliable, detasseling process can be avoided by using cytoplasmic male-sterile (CMS) inbreds. Plants of a CMS inbred are male sterile as a result of factors resulting from the cytoplasmic, as opposed to the nuclear, genome. Thus, this characteristic is inherited exclusively through the female parent in maize plants, since only the female provides cytoplasm to the fertilized seed. CMS plants are fertilized with pollen from another inbred that is not male-sterile. Pollen from the second inbred may or may not contribute genes that make the hybrid plants male-fertile. Usually seed from detasseled fertile maize and CMS produced seed of the same hybrid are blended to insure that adequate pollen loads are available for fertilization when the hybrid plants are grown.

There are several methods of conferring genetic male sterility available, such as multiple mutant genes at separate locations within the genome that confer male sterility, as disclosed in U.S. Pat. Nos. 4,654,465 and 4,727,219 to Brar et al. and chromosomal translocations as described by Patterson in U.S. Pat. Nos. 3,861,709 and 3,710,511. These and all patents referred to are incorporated by reference. In addition to these methods, Albertsen et al., of Pioneer Hi-Bred, U.S. patent application Ser. No. 07/848,433, have developed a system of nuclear male sterility which includes: identifying a gene which is critical to male fertility; silencing this native gene which is critical to male fertility; removing the native promoter from the essential male fertility gene and replacing it with an inducible promoter; inserting this genetically engineered gene back into the plant; and thus creating a plant that is male sterile because the inducible promoter is not "on" resulting in the male fertility gene not being transcribed. Fertility is restored by inducing, or turning "on", the promoter, which in turn allows the gene that confers male fertility to be transcribed.

There are many other methods of conferring genetic male sterility in the art, each with its own benefits and drawbacks. These methods use a variety of approaches such as delivering into the plant a gene encoding a cytotoxic substance associated with a male tissue specific promoter or an antisense system in which a gene critical to fertility is identified and an antisense to that gene is inserted in the plant (see: Fabinjanski, et al. EPO 89/3010153.8 publication no. 329,308 and PCT application PCT/CA90/00037 published as WO 90/08828).

Another system useful in controlling male sterility makes use of gametocides. Gametocides are not a genetic system, but rather a topical application of chemicals. These chemicals affect cells that are critical to male fertility. The application of these chemicals affects fertility in the plants only for the growing season in which the gametocide is applied (see Carlson, Glenn R., U.S. Pat. No. 4,936,904). Application of the gametocide, timing of the application and genotype specificity often limit the usefulness of the approach.

The use of male sterile inbreds is but one factor in the production of maize hybrids. The development of maize hybrids requires, in general, the development of homozygous inbred lines, the crossing of these lines, and the evaluation of the crosses. Breeding programs combine the genetic backgrounds from two or more inbred lines or various other broad-based sources into breeding pools from which new inbred lines are developed by selfing and selection of desired phenotypes. The new inbreds are crossed with other inbred lines and the hybrids from these crosses are evaluated to determine which of those have commercial potential.

There are many important factors to be considered in the art of plant breeding, such as the ability to recognize important morphological and physiological characteristics, the ability to design evaluation techniques for genotypic and phenotypic traits of interest, and the ability to search out and exploit the genes for the desired traits in new or improved combinations.

The objective of commercial maize hybrid line development programs is to develop new inbred lines to produce hybrids that combine to produce high grain yields and superior agronomic performance. The primary trait breeders seek is yield. However, many other major agronomic traits are of importance in hybrid combination and have an impact on yield or otherwise provide superior performance in hybrid combinations. Such traits include percent grain moisture at harvest, relative maturity, resistance to stalk breakage, resistance to root lodging, grain quality, and disease and insect resistance. In addition, the lines per se must have acceptable performance for parental traits such as seed yields, kernel sizes, pollen production, all of which affect ability to provide parental lines in sufficient quantity and quality for hybridization. These traits have been shown to be under genetic control and many if not all of the traits are affected by multiple genes.

Pedigree Breeding

The pedigree method of breeding is the mostly widely used methodology for new hybrid line development.

In general terms this procedure consists of crossing two inbred lines to produce the non-segregating F1 generation, and self pollination of the F1 generation to produce the F2 generation that segregates for all factors for which the inbred parents differ. An example of this process is set forth below. Variations of this generalized pedigree method are used, but all these variations produce a segregating generation which contains a range of variation for the traits of interest.

EXAMPLE 1 Hypothetical Example of Pedigree Breeding Program

Consider a cross between two inbred lines that differ for alleles at six loci. The parental genotypes are:

    ______________________________________                                         Parent 1         A b C d e F/A b C d e F                                       Parent 2         a B c D E f/a B c D E f                                       ______________________________________                                    

the F1 from a cross between these two parents is:

    ______________________________________                                         F1              A b C d e F/a B c D E f                                        ______________________________________                                    

Selfing F1 will produce an F2 generation including the following genotypes:

    ______________________________________                                                   A B c D E f/a b C d e F                                                        A B c D e f/a b C d E F                                                        A B c D e f/a b C d e F                                              ______________________________________                                    

The number of genotypes in the F2 is 36 for six segregating loci (729) and will produce (26)-2 possible new inbreds, (62 for six segregating loci).

Each inbred parent which is used in breeding crosses represents a unique combination of genes, and the combined effects of the genes define the performance of the inbred and its performance in hybrid combination. There is published evidence (Smith, O. S., J. S. C. Smith, S. L. Bowen, R. A. Tenborg and S. J. Wall, TAG 80:833-840 (1990)) that each of the lines are different and can be uniquely identified on the basis of genetically-controlled molecular markers.

It has been shown (Hallauer, Arnel R. and Miranda, J. B. Fo. Quantitative Genetics in Maize Breeding, Iowa State University Press, Ames Iowa, 1981) that most traits of economic value in maize are under the genetic control of multiple genetic loci, and that there are a large number of unique combinations of these genes present in elite maize germplasm. If not, genetic progress using elite inbred lines would no longer be possible. Studies by Duvick and Russell (Duvick, D. N., Maydica 37:69-79, (1992); Russell, W. A., Maydica XXIX:375-390 (1983)) have shown that over the last 50 years the rate of genetic progress in commercial hybrids has been between one and two percent per year.

The number of genes affecting the trait of primary economic importance in maize, grain yield, has been estimated to be in the range of 10-1000. Inbred lines which are used as parents for breeding crosses differ in the number and combination of these genes. These factors make the plant breeder's task more difficult. Compounding this is evidence that no one line contains the favorable allele at all loci, and that different alleles have different economic values depending on the genetic background and field environment in which the hybrid is grown. Fifty years of breeding experience suggests that there are many genes affecting grain yield and each of these has a relatively small effect on this trait. The effects are small compared to breeders' ability to measure grain yield differences in evaluation trials. Therefore, the parents of the breeding cross must differ at several of these loci so that the genetic differences in the progeny will be large enough that breeders can develop a line that increases the economic worth of its hybrids over that of hybrids made with either parent.

If the number of loci segregating in a cross between two inbred lines is n, the number of unique genotypes in the F2 generation is 3n and the number of unique inbred lines from this cross is {(2n)-2}. Only a very limited number of these combinations are useful. Only about 1 in 10,000 of the progeny from F2's are commercially useful.

By way of example, if it is assumed that the number of segregating loci in F2 is somewhere between 20 and 50, and that each parent is fixed for half the favorable alleles, it is then possible to calculate the approximate probabilities of finding an inbred that has the favorable allele at {(n/2)+m} loci, where n/2 is the number of favorable alleles in each of the parents and m is the number of additional favorable alleles in the new inbred. See Example 2 below. The number m is assumed to be greater than three because each allele has so small an effect that evaluation techniques are not sensitive enough to detect differences due to three or less favorable alleles. The probabilities in Example 2 are on the order of 10-5 or smaller and they are the probabilities that at least one genotype with (n/2)=m favorable alleles will exist.

To put this in perspective, the number of plants grown on 60 million acres (approximate United States corn acreage) at 25,000 plants/acre is 1.5×1012.

EXAMPLE 2

    ______________________________________                                         Probability of finding an inbred with m of n favorable alleles.                Assume each parent has n/2 of the favorable alleles and only 1/2 of            the combinations of loci are economically useful.                              No. of  No. of favorable                                                                           No. additional                                             segregating                                                                            alleles in Parents                                                                         favorable alleles in                                                                        Probability that                              loci (n)                                                                               (n/2)       new inbred   genotype occurs*                              ______________________________________                                         20      10          14           3 × 10-5                                24      12          16           2 × 10-5                                28      14          18           1 × 10-5                                32      16          20           8 × 10-6                                36      18          22           5 × 10-6                                40      20          24           3 × 10-6                                44      22          26           2 × 10-6                                48      24          28           1 × 10-6                                ______________________________________                                          *Probability that a useful combination exists, does not include the            probability of identifying this combination if it does exist.            

The possibility of having a usably high probability of being able to identify this genotype based on replicated field testing would be most likely smaller than this, and is a function of how large a population of genotypes is tested and how testing resources are allocated in the testing program.

SUMMARY OF THE INVENTION

According to the invention, there is provided a hybrid maize plant, designated as 35R57, produced by crossing two Pioneer Hi-Bred International, Inc. proprietary inbred maize lines. This hybrid maize plant is characterized by excellent yield and above average stalks. 35R57 has very good stand, brittle snap resistance and exhibits very good drought tolerance. 35R57 has above average performance across all yield environments. 35R57 has very good resistance to Northern Leaf Blight, Eye Spot and Goss' Wilt.

DEFINITIONS

In the description and examples that follow, a number of terms are used herein. In order to provide a clear and consistent understanding of the specification and claims, including the scope to be given such terms, the following definitions are provided. NOTE: ABS is in absolute terms and % MN is percent of the mean for the experiments in which the inbred or hybrid was grown. These designators will follow the descriptors to denote how the values are to be interpreted. Below are the descriptors used in the data tables included herein.

ANT ROT=ANTHRACNOSE STALK ROT (Colletotrichum graminicola). A 1 to 9 visual rating indicating the resistance to Anthracnose Stalk Rot. A higher score indicates a higher resistance.

BAR PLT=BARREN PLANTS. The percent of plants per plot that were not barren (lack ears).

BRT STK=BRITTLE STALKS. This is a measure of the stalk breakage near the time of pollination, and is an indication of whether a hybrid or inbred would snap or break near the time of flowering under severe winds. Data are presented as percentage of plants that did not snap in paired comparisons and on a 1 to 9 scale (9=highest resistance) in Characteristics Charts.

BU ACR=YIELD (BUSHELS/ACRE). Yield of the grain at harvest in bushels per acre adjusted to 15.5% moisture.

CLN=CORN LETHAL NECROSIS (synergistic interaction of maize chlorotic mottle virus (MCMV) in combination with either maize dwarf mosaic virus (MDMV-A or MDMV-B) or wheat streak mosaic virus (WSMV)). A 1 to 9 visual rating indicating the resistance to Corn Lethal Necrosis. A higher score indicates a higher resistance.

COM RST=COMMON RUST (Puccinia sorghi). A 1 to 9 visual rating indicating the resistance to Common Rust. A higher score indicates a higher resistance.

CRM=COMPARATIVE RELATIVE MATURITY (see PRM).

D/D=DRYDOWN. This represents the relative rate at which a hybrid will reach acceptable harvest moisture compared to other hybrids on a 1-9 rating scale. A high score indicates a hybrid that dries relatively fast while a low score indicates a hybrid that dries slowly.

D/E=DROPPED EARS. Represented in a 1 to 9 scale in the Characteristics Chart, where 9 is the rating representing the least, or no, dropped ears.

DIP ERS=DIPLODIA EAR MOLD SCORES (Diplodia maydis and Diplodia macrospora). A 1 to 9 visual rating indicating the resistance to Diplodia Ear Mold. A higher score indicates a higher resistance.

DRP EAR=DROPPED EARS. A measure of the number of dropped ears per plot and represents the percentage of plants that did not drop ears prior to harvest.

D/T=DROUGHT TOLERANCE. This represents a 1-9 rating for drought tolerance, and is based on data obtained under stress conditions. A high score indicates good drought tolerance and a low score indicates poor drought tolerance.

EAR HT=EAR HEIGHT. The ear height is a measure from the ground to the highest placed developed ear node attachment and is measured in inches. This is represented in a 1 to 9 scale in the Characteristics Chart, where 9 is highest.

EAR MLD=General Ear Mold. Visual rating (1-9 score) where a "1" is very susceptible and a "9" is very resistant. This is based on overall rating for ear mold of mature ears without determining the specific mold organism, and may not be predictive for a specific ear mold.

EAR SZ=EAR SIZE. A 1 to 9 visual rating of ear size. The higher the rating the larger the ear size.

ECB 1LF=EUROPEAN CORN BORER FIRST GENERATION LEAF FEEDING (Ostrinia nubilalis). A 1 to 9 visual rating indicating the resistance to preflowering leaf feeding by first generation European Corn Borer. A higher score indicates a higher resistance.

ECB 2IT=EUROPEAN CORN BORER SECOND GENERATION INCHES OF TUNNELING (Ostrinia nubilalis). Average inches of tunneling per plant in the stalk.

ECB 2SC=EUROPEAN CORN BORER SECOND GENERATION (Ostrinia nubilalis). A 1 to 9 visual rating indicating post flowering degree of stalk breakage and other evidence of feeding by European Corn Borer, Second Generation. A higher score indicates a higher resistance.

ECB DPE=EUROPEAN CORN BORER DROPPED EARS (Ostrinia nubilalis). Dropped ears due to European Corn Borer. Percentage of plants that did not drop ears under second generation corn borer infestation.

E/G=EARLY GROWTH. This represents a 1 to 9 rating for early growth, scored when two leaf collars are visible. A higher rating indicates a teller plant than does a lower rating.

EST CNT=EARLY STAND COUNT. This is a measure of the stand establishment in the spring and represents the number of plants that emerge on per plot basis for the inbred or hybrid.

EYE SPT=Eye Spot (Kabatiella zeae or Aureobasidium zeae). A 1 to 9 visual rating indicating the resistance to Eye Spot. A higher score indicates a higher resistance.

FUS ERS=FUSARIUM EAR ROT SCORE (Fusarium moniliforme or Fusarium subglutinans). A 1 to 9 visual rating indicating the resistance to Fusarium ear rot. A higher score indicates a higher resistance.

G/A=GRAIN APPEARANCE. Appearance of grain in the grain tank (scored down for mold, cracks, red streak, etc.).

GDU=Growing Degree Units. Using the Barger Heat Unit Theory, that assumes that maize growth occurs in the temperature range 50° F.-86° F. and that temperatures outside this range slow down growth; the maximum daily heat unit accumulation is 36 and the minimum daily heat unit accumulation is 0. The seasonal accumulation of GDU is a major factor in determining maturity zones.

GDU PHY=GDU TO PHYSIOLOGICAL MATURITY. The number of growing degree units required for an inbred or hybrid line to have approximately 50 percent of plants at physiological maturity from time of planting. Growing degree units are calculated by the Barger method.

GDU SHD=GDU TO SHED. The number of growing degree units (GDUs) or heat units required for an inbred line or hybrid to have approximately 50 percent of the plants shedding pollen and is measured from the time of planting. Growing degree units are calculated by the Barger Method, where the heat units for a 24-hour period are: ##EQU1##

The highest maximum temperature used is 86° F. and the lowest minimum temperature used is 50° F. For each inbred or hybrid it takes a certain number of GDUs to reach various stages of plant development.

GDU SLK=GDU TO SILK. The number of growing degree units required for an inbred line or hybrid to have approximately 50 percent of the plants with silk emergence from time of planting. Growing degree units are calculated by the Barger Method as given in GDU SHD definition.

GIB ERS=GIBBERELLA EAR ROT (PINK MOLD) (Gibberella zeae). A 1 to 9 visual rating indicating the resistance to Gibberella Ear Rot. A higher score indicates a higher resistance.

GLF SPT=Gray Leaf Spot (Cercospora zeae-maydis). A 1 to 9 visual rating indicating the resistance to Gray Leaf Spot. A higher score indicates a higher resistance.

GOS WLT=Goss' Wilt (Corynebacterium nebraskense). A 1 to 9 visual rating indicating the resistance to Goss' Wilt. A higher score indicates a higher resistance.

GRN APP=GRAIN APPEARANCE. This is a 1 to 9 rating for the general appearance of the shelled grain as it is harvested based on such factors as the color of harvested grain, any mold on the grain, and any cracked grain. High scores indicate good grain quality.

H/POP=YIELD AT HIGH DENSITY. Yield ability at relatively high plant densities on 1-9 relative rating system with a higher number indicating the hybrid responds well to high plant densities for yield relative to other hybrids. A 1, 5, and 9 would represent very poor, average, and very good yield response, respectively, to increased plant density.

HC BLT=HELMINTHOSPORIUM CARBONUM LEAF BLIGHT (Helminthosporium carbonum). A 1 to 9 visual rating indicating the resistance to Helminthosporium infection. A higher score indicates a higher resistance.

HD SMT=HEAD SMUT (Sphacelotheca reiliana). This score indicates the percentage of plants not infected.

INC D/A=GROSS INCOME (DOLLARS PER ACRE). Relative income per acre assuming drying costs of two cents per point above 15.5 percent harvest moisture and current market price per bushel.

INCOME/ACRE. Income advantage of hybrid to be patented over other hybrid on per acre basis.

INC ADV=GROSS INCOME ADVANTAGE. GROSS INCOME advantage of variety #1 over variety #2.

L/POP=YIELD AT LOW DENSITY. Yield ability at relatively low plant densities on a 1-9 relative system with a higher number indicating the hybrid responds well to low plant densities for yield relative to other hybrids. A 1, 5, and 9 would represent very poor, average, and very good yield response, respectively, to low plant density.

MDM CPX=MAIZE DWARF MOSAIC COMPLEX (MDMV=Maize Dwarf Mosaic Virus and MCDV=Maize Chlorotic Dwarf Virus). A 1 to 9 visual rating indicating the resistance to Maize Dwarf Mosaic Complex. A higher score indicates a higher resistance.

MST=HARVEST MOISTURE. The moisture is the actual percentage moisture of the grain at harvest.

MST ADV=MOISTURE ADVANTAGE. The moisture advantage of variety #1 over variety #2 as calculated by: MOISTURE of variety #2-MOISTURE of variety #1=MOISTURE ADVANTAGE of variety #1.

NLF BLT=Northern Leaf Blight (Helminthosporium turcicum or Exserohilum turcicum). A 1 to 9 visual rating indicating the resistance to Northern Leaf Blight. A higher score indicates a higher resistance.

PHY CRM=CRM at physiological maturity.

PLT HT=PLANT HEIGHT. This is a measure of the height of the plant from the ground to the tip of the tassel in inches. This is represented as a 1 to 9 scale, 9 highest, in the Characteristics Chart.

POL SC=POLLEN SCORE. A 1 to 9 visual rating indicating the amount of pollen shed. The higher the score the more pollen shed.

POL WT=POLLEN WEIGHT. This is calculated by dry weight of tassels collected as shedding commences minus dry weight from similar tassels harvested after shedding is complete.

It should be understood that the inbred can, through routine manipulation of cytoplasmic or other factors, be produced in a male-sterile form. Such embodiments are also contemplated within the scope of the present claims.

POP K/A=PLANT POPULATIONS. Measured as 1000s per acre.

POP ADV=PLANT POPULATION ADVANTAGE. The plant population advantage of variety #1 over variety #2 as calculated by PLANT POPULATION of variety #2-PLANT POPULATION of variety #1=PLANT POPULATION ADVANTAGE of variety #1.

PRM=PREDICTED Relative Maturity. This trait, predicted relative maturity, is based on the harvest moisture of the grain. The relative maturity rating is based on a known set of checks and utilizes standard linear regression analyses and is referred to as the Comparative Relative Maturity Rating System that is similar to the Minnesota Relative Maturity Rating System.

PRM SHD=A relative measure of the growing degree units (GDU) required to reach 50% pollen shed. Relative values are predicted values from the linear regression of observed GDU's on relative maturity of commercial checks.

PRO=PROTEIN RATING . Rating on a 1 to 9 scale comparing relative amount of protein in the grain compared to hybrids of similar maturity. A "1" score difference represents a 0.4 point change in grain protein percent (e.g., 8.0% to 8.4%).

P/Y=PROTEIN/YIELD RATING. Indicates, on a 1 to 9 scale, the economic value of a hybrid for swine and poultry feeders. This takes into account the income due to yield, moisture and protein content.

ROOTS (%)=Percent of stalks NOT root lodged at harvest.

R/L=ROOT LODGING. A 1 to 9 rating indicating the level of root lodging resistance. The higher score represents higher levels of resistance.

RT LDG=ROOT LODGING. Root lodging is the percentage of plants that do not root lodge; plants that lean from the vertical axis as an approximately 30° angle or greater would be counted as root lodged.

RTL ADV=ROOT LODGING ADVANTAGE. The root lodging advantage of variety #1 over variety #2.

S/L=STALK LODGING. A 1 to 9 rating indicating the level of stalk lodging resistance. The higher scores represent higher levels of resistance.

SCT GRN=SCATTER GRAIN. A 1 to 9 visual rating indicating the amount of scatter grain (lack of pollination or kernel abortion) on the ear. The higher the score the less scatter grain.

SDG VGR=SEEDLING VIGOR. This is the visual rating (1 to 9) of the amount of vegetative growth after emergence at the seedling stage (approximately five leaves). A higher score indicates better vigor.

SEL IND=SELECTION INDEX. The selection index gives a single measure of the hybrid's worth based on information for up to five traits. A maize breeder may utilize his or her own set of traits for the selection index. One of the traits that is almost always included is yield. The selection index data presented in the tables represent the mean value averaged across testing stations.

SLF BLT=SOUTHERN LEAF BLIGHT (Helminthosporium maydis or Bipolaris maydis). A 1 to 9 visual rating indicating the resistance to Southern Leaf Blight. A higher score indicates a higher resistance.

SLK CRM=CRM at Silking.

SOU RST=SOUTHERN RUST (Puccinia polysora). A 1 to 9 visual rating indicating the resistance to Southern Rust. A higher score indicates a higher resistance.

STA GRN=STAY GREEN. Stay green is the measure of plant health near the time of black layer formation (physiological maturity). A high score indicates better late-season plant health.

STAND (%)=Percent of stalks standing at harvest.

STD ADV=STALK STANDING ADVANTAGE. The advantage of variety #1 over variety #2 for the trait STK CNT.

STK CNT=NUMBER OF PLANTS. This is the final stand or number of plants per plot.

STK LDG=STALK LODGING. This is the percentage of plants that did not stalk lodge (stalk breakage) as measured by either natural lodging or pushing the stalks and determining the percentage of plants that break below the ear.

STW WLT=Stewart's Wilt (Erwinia stewartii). A 1 to 9 visual rating indicating the resistance to Stewart's Wilt. A higher score indicates a higher resistance.

TAS BLS=TASSEL BLAST. A 1 to 9 visual rating was used to measure the degree of blasting (necrosis due to heat stress) of the tassel at the time of flowering. A 1 would indicate a very high level of blasting at time of flowering, while a 9 would have no tassel blasting.

TAS SZ=TASSEL SIZE. A 1 to 9 visual rating was used to indicate the relative size of the tassel. The higher the rating the larger the tassel.

TAS WT=TASSEL WEIGHT. This is the average weight of a tassel (grams) just prior to pollen shed.

TEX EAR=EAR TEXTURE. A 1 to 9 visual rating was used to indicate the relative hardness (smoothness of crown) of mature grain. A 1 would be very soft (extreme dent) while a 9 would be very hard (flinty or very smooth crown).

TIL LER=TILLERS. A count of the number of tillers per plot that could possibly shed pollen was taken. Data is given as a percentage of tillers: number of tillers per plot divided by number of plants per plot.

TST WT (CHARACTERISTICS CHART)=Test weight on a 1 to 9 rating scale with a 9 being the highest rating.

TST WT=TEST WEIGHT (UNADJUSTED). The measure of the weight of the grain in pounds for a given volume (bushel).

TST WTA=TEST WEIGHT ADJUSTED. The measure of the weight of the grain in pounds for a given volume (bushel) adjusted for 15.5 percent moisture.

TSW ADV=TEST WEIGHT ADVANTAGE. The test weight advantage of variety #1 over variety #2.

WIN M %=PERCENT MOISTURE WINS.

WIN Y %=PERCENT YIELD WINS.

YLD=YIELD. It is the same as BU ACR ABS.

YLD ADV=YIELD ADVANTAGE. The yield advantage of variety #1 over variety #2 as calculated by: YIELD of variety #1-YIELD variety #2=yield advantage of variety #1.

YLD SC=YIELD SCORE. A 1 to 9 visual rating was used to give a relative rating for yield based on plot ear piles. The higher the rating the greater visual yield appearance.

DETAILED DESCRIPTION OF THE INVENTION

Pioneer Brand Hybrid 35R57 is a single cross, yellow endosperm, dent maize hybrid which is high yielding with very good brittle snap resistance. Hybrid 35R57 exhibits above average stalks and good drought tolerance. The hybrid is broadly adapted with above average resistance to Northern Leaf Blight, Eye Spot and Goss's Wilt.

This hybrid has the following characteristics based on the data collected primarily at Johnston, Iowa.

                                      TABLE 1                                      __________________________________________________________________________     VARIETY DESCRIPTION INFORMATION                                                VARIETY = 35R57                                                                __________________________________________________________________________     1. TYPE: (describe intermediate types in Comments section):                    2           1 = Sweet 2 = Dent 3 = Flint 4 = Flour 5 = Pop 6                               = Ornamental                                                       2. MATURITY:                                                                   DAYS HEAT UNITS                                                                064  1,248.5                                                                               From emergence to 50% of plants in silk                            065  1,268.0                                                                               From emergence to 50% of plants in pollen                          004  0,076.5                                                                               From 10% to 90% pollen shed                                        068  1,189.5                                                                               From 50% silk to harvest at 25% moisture                           3. PLANT:                                                                                                                Standard                                                                            Sample                                                                    Deviation                                                                           Size                            0,260.0                                                                             cm     Plant Height (to tassel tip)  5.66  2                              0,090.0                                                                             cm     Ear Height (to base of top ear node)                                                                         5.66  2                              0,016.9                                                                             cm     Length of Top Ear Internode   0.42 10                              1           Average Number of Tillers     0.00  2                              1.0         Average Number of Ears per Stalk                                                                             0.00  2                              1.0         Anthocyanin of Brace Roots: 1 = Absent 2 = Faint 3 = Moderate                  4 = Dark                                                           4. LEAF:                                                                                                                 Standard                                                                            Sample                                                                    Deviation                                                                           Size                            009.3                                                                               cm     Width of Ear Node Leaf        1.27 10                              090.8                                                                               cm     Length of Ear Node Leaf       5.37 10                              06.0        Number of leaves above top ear                                                                               0.00 10                              041.5       Degrees Leaf, Angle (measure from 2nd leaf above                                                             6.36  2                                          ear at anthesis to stalk above leaf)                               03          Leaf Color  Dark Green  (Munsell code)  5GY44                      1.0         Leaf Sheath Pubescence (Rate on scale from 1 = none to 9 =                     like peach                                                                     fuzz)                                                              6.5         Marginal Waves (Rate on scale from 1 = none to 9 = many)           5.5         Longitudinal Creases (Rate on scale from 1 = none to 9 =                       many)                                                              5. TASSEL:                                                                                                               Standard                                                                            Sample                                                                    Deviation                                                                           Size                            06.0        Number of Primary Lateral Branches  5                              039.0       Branch Angle from Central Spike     1                              59.4 cm     Tassel Length (from top leaf collar to tassel                                                                      1p)                            8.0         Pollen Shed (rate on scale from 0 = male sterile to 9 = heavy                  shed)                                                              11          Anther Color  Pink  (Munsell code)  7.5R64                         01          Glume Color  Light Green  (Munsell code)  5GY76                    1.0         Bar Glumes (Glume Bands): 1 = Absent 2 = Present                   22          Peduncle Length (cm. from top leaf to basal branches)              6a. EAR (Unhusked Data):                                                       11          Silk Color (3 days after emergence)  Pink  (Munsell code)                      7.5R66                                                             2           Fresh Husk Color (25 days after 50% silking)  Medium Green                     (Munsell code)  5GY66                                              21          Dry Husk Color (65 days after 50% silking)  Buff  (Munsell                     code)                                                                          2.5Y8.54                                                           2           Position of Ear at Dry Husk Stage: 1 = Upright 2                               = Horizontal                                                                   3 = Pendant  Horizontal                                            4           Husk Tightness (Rate of Scale from 1 = very loose to 9 = very                  tight)                                                             2           Husk Extension (at harvest): 1 = Short (ears exposed) 2 =                      Medium (<8 cm)                                                                 3 = Long (8-10 cm beyond ear tip) 4 = Very Long (>10 cm)                       Medium                                                             6b. EAR (Husked Ear Data):                                                                                               Standard                                                                            Sample                                                                    Deviation                                                                           Size                            18   cm     Ear Length                    0.00 10                              47   mm     Ear Diameter at mid-point     0.71 10                              183  gm     Ear Weight                    12.02                                                                               10                              17          Number of Kernel Rows         0.71 10                              2           Kernel Rows: 1 = Indistinct 2 = Distinct  Distinct                 1           Row Alignment: 1 = Straight 2 = Slightly Curved 3 = Spiral                     Straight                                                           11   cm     Shank Length                  0.71 10                              2           Ear Taper: 1 = Slight 2 = Average 3 = Extreme  Average             7. KERNEL (Dried):                                                                                                       Standard                                                                            Sample                                                                    Deviation                                                                           Size                            13   mm     Kernel Length                 0.71 10                              8    mm     Kernel Width                  0.00 10                              4    mm     Kernel Thickness              0.00 10                              8           % Round Kernels (Shape Grade) 2.83  2                              1           Aleurone Color Pattern: 1 = Homozygous 2 = Segregating                         Homozygous                                                         7           Aluerone Color  Yellow  (Munsell code) 2.5Y812                     6           Hard Endosperm Color  Pale Yellow  (Munsell code)  2.5Y810         3           Endosperm Type:  Normal Starch                                                 1 = Sweet (Su1) 2 = Extra Sweet (sh2) 3 = Normal Starch                        4 = High Amylose Starch 5 = Waxy Starch 6 = High Protein                       7 = High Lysine 8 = Super Sweet (se) 9 = High Oil                              10 = Other                                                         30   gm     Weight per 100 Kernels (unsized sample)                                                                      2.83  2                              8. COB:                                                                                                                  Standard                                                                            Sample                                                                    Deviation                                                                           Size                            24   mm     Cob Diameter at mid-point     1.41 10                              14          Cob Color  Red  (Munsell code)  10R44                                          Cob Strength 1 = Weak 2 = Strong                                   9. DISEASE RESISTANCE (Rate from 1 (most susceptible) to 9 (most               resistant); leave blank                                                        if not tested; leave Race or Strain options blank if polygenic):               A. Leaf Blights, Wilts, and Local Infection Diseases                                Anthracnose Leaf Blight (Colletotrichum graminicola)                           Common Rust (Puccinia sorghi)                                                  Common Smut (Ustilago                                                     6    Eyespot (Kabatiella zeae)  maydis)                                        7    Goss's Wilt (Clavibacter michiganense spp. nebraskense)                   4    Gray Leaf Spot (Cercospora zeae-maydis)                                        Helminthosporium Leaf Spot (Bipolaris zeicola)  Race--                    6    Northern Leaf Blight (Exserohilum turcicum)  Race--                            Southern Leaf Blight (Bipolaris maydis)  Race--                           5    Southern Rust (Puccinia polysora)                                              Stewart's Wilt (Erwinia stewartii)                                             Other (Specify)--                                                         B. Systemic Diseases                                                                Corn Lethal Necrosis (MCMV and MDMV)                                           Head Smut (Sphacelotheca reiliana)                                             Maize Chlorotic Dwarf Virus (MDV)                                              Maize Chlorotic Mottle Virus (MCMV)                                            Maize Dwarf Mosaic Virus (MDMV)                                                Sorghum Downy Mildew of Corn (Peronosclerospora sorghi)                        Other (Specify)--                                                         C. Stalk Rots                                                                  3    Anthracnose Stalk Rot (Colletotrichum graminicola)                             Diplodia Stalk Rot (Stenocarpella maydis)                                      Fusarium Stalk Rot (Fusarium moniliforme)                                      Gibberella Stalk Rot (Gibberella zeae)                                         Other (Specify)--                                                         D. Ear and Kernel Rots                                                              Aspergillus Ear and Kernel Rot (Aspergillus flavus)                            Diplodia Ear Rot (Stenocarpella maydis)                                   4    Fusarium Ear and Kernel Rot (Fusarium moniliforme)                        4    Gibberella Ear Rot (Gibberella zeae)                                           Other (Specify)--                                                              Banks grass Mite (Oligonychus pratensis)                                       Corn Worm (Helicoverpa zea)                                                    Leaf Feeding                                                                   Silk Feeding                                                                   mg larval wt.                                                                  Ear Damage                                                                     Corn Leaf Aphid (Rhopalosiphum maidis)                                         Corn Sap Beetle (Carpophilus dimidiatus                                        European Corn Borer (Ostrinia nubilalis)                                  4    1st Generation (Typically Whorl Leaf Feeding)                             5    2nd Generation (Typically Leaf Sheath-Collar Feeding)                          Stalk Tunneling                                                                cm tunneled/plant                                                              Fall Armyworm (Spodoptera fruqiperda)                                          Leaf Feeding                                                                   Silk Feeding                                                                   mg Larval wt.                                                                  Maize Weevil (Sitophilus zeamaize                                              Northern Rootworm (Diabrotica barberi)                                         Southern Rootworm (Diabrotica undecimpunctata)                                 Southwestern Corn Borer (Diatreaea grandiosella)                               Leaf Feeding                                                                   Stalk Tunneling                                                                cm tunneled/plant                                                              Two-spotted Spider Mite (Tetranychus urticae)                                  Western Rootworm (Diabrotica virgifrea virgifera)                              Other (Specify)--                                                         11. AGRONOMIC TRAITS:                                                          5           Staygreen (at 65 days after anthesis) (Rate on a scale from 1                  = worst to                                                                     excellent)                                                         0.0         % Dropped Ears (at 65 days after anthesis)                                     % Pre-anthesis Brittle Snapping                                                % Pre-anthesis Root Lodging                                        6.9         Post-anthesis Root Lodging (at 65 days after anthesis)             10,480      Kg/ha Yield (at 12-13% grain moisture)                             __________________________________________________________________________

Research Comparisons for Pioneer Hybrid 35R57

Comparisons of characteristics for Pioneer Brand Hybrid 35R57 were made against Pioneer Brand Hybrid 3531, 3547, 3563 and 3578.

Table 2A compares Pioneer Hybrid 35R57 and Pioneer Brand 3531 a hybrid of similar maturity. The results show that 35R57 is significantly higher yielding with a somewhat higher test weight than hybrid 3531. Hybrid 35R57 demonstrates significantly superior stay green and significantly better resistance to brittle snap than hybrid 3531. 35R57 exhibits significantly higher resistance to stalk lodging and a significantly better grain appearance than hybrid 3531. The 35R57 hybrid also demonstrates superior resistance to Northern Leaf Blight, and eye spot than hybrid 3531.

Table 2B compares Pioneer Hybrid 35R57 and a hybrid of similar maturity, Pioneer Hybrid 3547. The results indicate that Hybrid 35R57 is significantly higher yielding than the 3547 hybrid. The 35R57 hybrid also demonstrates higher resistance to brittle snap than the 3547 hybrid. Both hybrids exhibit good stalks with above average resistance to lodging and to brittle snap.

Table 2C compares Pioneer Hybrid 35R57 and Pioneer Hybrid 3563 a hybrid of similar maturity. The results show that Hybrid 35R57 is significantly higher yielding than hybrid 3563. The 35R57 hybrid demonstrates significantly superior brittle snap resistance and is earlier to mature with significantly fewer growing degree units to silk and to shed than hybrid 3563. The 35R57 hybrid exhibits lower seedling vigor than hybrid 3563. Both hybrids demonstrate low harvest moisture and above average stalk lodge resistance.

Table 2D compares Pioneer Hybrid 35R57 and Pioneer Hybrid 3578, a hybrid of similar maturity. According to the results, hybrid 35R57 is significantly higher yielding, with lower harvest moisture and significantly higher test weight than hybrid 3578. The Hybrid 35R57 hybrid demonstrates significantly higher resistance to stalk lodge and higher brittle snap resistance than hybrid 3578. 35R57 exhibits shorter plant stature than hybrid 3578. Both hybrids have below average resistance to root lodging.

                                      TABLE 2A                                     __________________________________________________________________________     HYBRID COMPARISON REPORT                                                       VARIETY #1 = 35R57                                                             VARIETY #2 = 3531                                                              __________________________________________________________________________                       PRM  BU    BU          TST  SDG   EST  GDU                               PRM   SHD  ACR   ACR   MST   WT   VGR   CNT  SHD                               ABS   ABS  ABS   % MN  % MN  ABS  % MN  % MN %                     __________________________________________________________________________                                                              MN                    TOTAL SUM                                                                              1   104   106  160.2 106   99    55.6 90    100  100                           2   103   103  146.6 97    97    55.3 99    102  98                            LOCS                                                                               27    39   108   108   112   79   85    137  64                            REPS                                                                               27    39   123   123   127   91   98    155  71                            DIFF                                                                               1     3    13.6  9     2     O.3  10    2    3                             PR > T                                                                             .004# .000#                                                                               .000# .000# .000# .086*                                                                               .002# .126 .000#                 __________________________________________________________________________                 GDU   STK  PLT   EAR   RT    STA  STK   BRT  GRN                               SLK   CNT  HT    HT    LDG   GRN  LDG   STK  APP                               % MN  % MN % MN  % MN  % MN  % MN % MN  % MN %                     __________________________________________________________________________                                                              MN                    TOTAL SUM                                                                              1   100   100  98    96    101   89   103   108  100                           2   97    101  99    100   98    72   97    104  88                            LOCS                                                                               41    216  79    79    44    64   92    18   18                            REPS                                                                               47    271  87    87    50    72   105   31   21                            DIFF                                                                               3     1    1     4     3     17   6     4    12                            PR > T                                                                             .000# .086*                                                                               .008# .001# .479  .000#                                                                               .000# .047+                                                                               .019+                 __________________________________________________________________________                 DRP   GLF  NLF   GOS   ANT   HD   GIB   EYE  SOU                               EAR   SPT  BLT   WLT   ROT   SMT  ERS   SPT  RST                               % MN  ABS  ABS   ABS   ABS   ABS  ABS   ABS  ABS                   __________________________________________________________________________     TOTAL SUM                                                                              1   100   3.7  6.1   7.3   1.0   89.0 2.5   5.5  5.0                           2   100   3.1  3.9   7.5   3.5   86.9 2.8   4.0  3.0                           LOCS                                                                               61    9    9     3     1     2    2     4    1                             REPS                                                                               70    16   18    6     2     6    3     4    1                             DIFF                                                                               0     0.7  2.1   0.2   2.5   2.1  0.3   1.5  2.0                           PR > T                                                                             .999  .022+                                                                               .001# .826        .643 .874  .014+                      __________________________________________________________________________                 ECB   ECB  ECB                                                                 DPE   1LF  2SC                                                                 ABS   ABS  ABS                                                     __________________________________________________________________________     TOTAL SUM                                                                              1   99.7  4.0  3.5                                                             2   99.2  6.5  3.9                                                             LOCS                                                                               12    2    11                                                              REPS                                                                               13    2    11                                                              DIFF                                                                               0.5   2.5  0.4                                                             PR > T                                                                             .286  .126 .420                                                    __________________________________________________________________________      * = 10% SIG                                                                    + = 5% SIG                                                                     # = 1% SIG                                                               

                                      TABLE 2B                                     __________________________________________________________________________     HYBRID COMPARISON REPORT                                                       VARIETY #1 = 35R57                                                             VARIETY #2 = 3547                                                              __________________________________________________________________________                       PRM  BU    BU          TST  SDG   EST  GDU                               PRM   SHD  ACR   ACR   MST   WT   VGR   CNT  SHD                               ABS   ABS  ABS   % MN  % MN  ABS  % MN  % MN %                     __________________________________________________________________________                                                              MN                    TOTAL SUM                                                                              1   104   106  162.9 108   102   54.8 95    99   101                           2   104   104  154.8 103   103   56.3 90    103  100                           LOCS                                                                               16    18   48    48    50    26   31    37   29                            REPS                                                                               16    18   65    65    67    32   43    46   34                            DIFF                                                                               1     2    8.1   5     2     1.5  4     4    1                             PR > T                                                                             .041+ .000#                                                                               .000# .001# *221  .000#                                                                               *365  .067*                                                                               .000#                 __________________________________________________________________________                 GDU   STK  PLT   EAR   RT    STA  STK   BRT  DRP                               SLK   CNT  HT    HT    LDG   GRN  LDG   STK  EAR                               % MN  % MN % MN  % MN  % MN  % MN % MN  % MN %                     __________________________________________________________________________                                                              MN                    TOTAL SUM                                                                              1   101   99   99    98    98    96   103   110  100                           2   100   101  99    96    104   94   104   102  100                           LOCS                                                                               22    79   28    28    29    24   34    7    24                            REPS                                                                               27    115  36    36    43    31   46    14   30                            DIFF                                                                               1     1    0     2     6     2    2     7    o                             PR > T                                                                             .053* .254 .999  .309  .150  .817 .316  .163 .999                  __________________________________________________________________________                 NLF   ECB  ECB   ECB                                                           BLT   DPE  1LF   25C                                                           ABS   ABS  ABS   ABS                                               __________________________________________________________________________     TOTAL SUM                                                                              1   7.5   99.1 4.0   4.4                                                       2   6.5   98.8 6.0   5.2                                                       LOCS                                                                               1     8    1     11                                                        REPS                                                                               2     8    1     16                                                        DIFF                                                                               1.0   0.3  2.0   0.8                                                       PR > T    .660       .000#                                             __________________________________________________________________________      * = 10% SIG                                                                    + = 5% SIG                                                                     # = 1% SIG                                                               

                                      TABLE 2C                                     __________________________________________________________________________     HYBRID COMPARISON REPORT                                                       VARIETY #1 = 35R57                                                             VARIETY #2 = 3563                                                              __________________________________________________________________________                       PRM  BU    BU          TST  SDG   EST  GDU                               PRM   SHD  ACR   ACR   MST   WT   VGR   CNT  SHD                               ABS   ABS  ABS   % MN  % MN  ABS  % MN  % MN %                     __________________________________________________________________________                                                              MN                    TOTAL SUM                                                                              1   104   106  160.8 104   98    55.6 87    99   100                           2   104   106  156.5 101   98    56.9 109   105  101                           LOCS                                                                               38    47   140   140   144   93   128   184  93                            REPS                                                                               38    47   160   160   164   105  151   205  107                           DIFF                                                                               0     1    4.3   3     0     1.3  22    5    1                             PR > T                                                                             .999  .044+                                                                               .013+ .005# .999  .000#                                                                               .000# .000#                                                                               .000#                 __________________________________________________________________________                 GDU   STK  PLT   EAR   RT    STA  STK   BRT  GRN                               SLK   CNT  HT    HT    LDG   GRN  LDG   STK  APP                               % MN  % MN % MN  % MN  % MN  % MN % MN  % MN %                     __________________________________________________________________________                                                              MN                    TOTAL SUM                                                                              1   99    100  97    95    102   80   103   107  98                            2   101   103  102   95    116   110  101   90   98                            LOCS                                                                               50    400  118   118   59    105  104   22   22                            REPS                                                                               56    480  133   133   70    119  123   45   25                            DIFF                                                                               2     2    5     0     14    31   2     17   1                             PR > T                                                                             .000# .000#                                                                               .000# .999  .016+ .000#                                                                               .099* .004#                                                                               .827                  __________________________________________________________________________                 DRP   GLF  NLF   GOS   ANT   HD   GIB   EYE  SOU                               EAR   SPT  BLT   WLT   ROT   SMT  ERS   SPT  RST                               % MN  ABS  ABS   ABS   ABS   ABS  ABS   ABS  ABS                   __________________________________________________________________________     TOTAL SUM                                                                              1   100   3.4  6.1   7.3   1.0   89.0 2.0   5.5  5.0                           2   100   3.8  6.1   7.8   2.0   99.0 6.0   5.8  3.0                           LOCS                                                                               62    15   9     3     1     2    1     4    1                             REPS                                                                               71    21   18    6     2     6    2     4    1                             DIFF                                                                               1     0.4  0.1   0.5   1.0   10.0 4.0   0.3  2.0                           PR > T                                                                             .015+ .143 .892  .423        .417       .638                       __________________________________________________________________________                 ECB   ECB  ECB                                                                 DPE   1LF  2SC                                                                 ABS   ABS  ABS                                                     __________________________________________________________________________     TOTAL SUM                                                                              1   88.6  4.0  3.7                                                             2   88.5  2.7  5.0                                                             LOCS                                                                               16    3    12                                                              REPS                                                                               22    3    12                                                              DIFF                                                                               0.1   1.3  1.3                                                             PR > T                                                                             .796  .057*                                                                               .005#                                                   __________________________________________________________________________      * = 10% SIG                                                                    + = 5% SIG                                                                     # = 1% SIG                                                               

                                      TABLE 2D                                     __________________________________________________________________________     HYBRID COMPARISON REPORT                                                       VARIETY #1 = 35R57                                                             VARIETY #2 = 3578                                                              __________________________________________________________________________                    PRM BU  BU      TST SDG EST GDU                                            PRM SHD ACR ACR MST WT  VGR CNT SHD                                            ABS ABS ABS % MN                                                                               % MN                                                                               ABS % MN                                                                               % MN                                                                               % MN                                __________________________________________________________________________     TOTAL SUM                                                                             1   103 105 166.5                                                                              105 100 54.7                                                                               93  97  101                                        2   105 104 155.3                                                                              99  103 53.0                                                                               105 103 100                                        LOCS                                                                               7   8   25  25  26  12  11  10  14                                         REPS                                                                               7   8   42  42  43  17  22  17  22                                         DIFF                                                                               1   1   11.2                                                                               6   3   1.7 12  7   1                                          PR > T                                                                             .067*                                                                              .049+                                                                              .015+                                                                              .018+                                                                              .010+                                                                              .004#                                                                              .077*                                                                              .526                                                                               .052*                               __________________________________________________________________________                GDU STK PLT EAR RT  STA STK BRT DRP                                            SLK CNT HT  HT  LDG GRN LDG STK EAR                                            % MN                                                                               % MN                                                                               % MN                                                                               % MN                                                                               % MN                                                                               % MN                                                                               % MN                                                                               % MN                                                                               % MN                                __________________________________________________________________________     TOTAL SUM                                                                             1   101 98  99  98  98  93  103 109 100                                        2   100 101 100 101 98  102 100 84  99                                         LOCS                                                                               9   36  14  14  15  12  19  5   11                                         REPS                                                                               13  69  24  24  28  23  33  12  17                                         DIFF                                                                               1   3   1   2   0   8   3   26  1                                          PR > T                                                                             .284                                                                               .167                                                                               .190                                                                               .247                                                                               .999                                                                               .354                                                                               .031+                                                                              .119                                                                               .112                                __________________________________________________________________________                ECB ECB ECB                                                                    DPE 1LF 2SC                                                                    ABS ABS ABS                                                         __________________________________________________________________________     TOTAL SUM                                                                             1   64.3                                                                               4.0 6.3                                                                2   68.0                                                                               7.0 5.8                                                                LOCS                                                                               5   1   3                                                                  REPS                                                                               10  1   6                                                                  DIFF                                                                               3.7 3.0 0.5                                                                PR > T                                                                             .517    .225                                                        __________________________________________________________________________      * = 10% SIG                                                                    + = 5% SIG                                                                     # = 1% SIG                                                               

Strip Test Data for Hybrid 35R57

Comparison data was collected from strip tests that were grown by farmers. Each hybrid was grown in strips of 4, 6, 8, 12, etc. rows in fields depending on the size of the planter used. The data was collected from strip tests that had the hybrids in the same area and weighed. The moisture percentage was determined and bushels per acre was adjusted to 15.5 percent moisture. The number of comparisons represent the number of locations or replications for the two hybrids that were grown in the same field in close proximity and compared.

Comparison strip testing was done between Pioneer Brand Hybrid 35R57 and Pioneer Brand Hybrids 3578, 3531, 3547, and 3563. The comparisons come from the hybrid's adapted growing areas in the United States.

These results are presented in Table 3. Hybrid 35R57 has a yield advantage over all of the hybrids. The average yield advantage is 4.9 bushels per acre and ranged from 4.0 to 5.3 bushels per acre. Hybrid 35R57 showed a greater income advantage to the farmer based on adjusted growth income over all hybrids compared. The income advantage per acre ranged from $9.76 to $15.96. Hybrid 35R57's yield and income advantage plus its advantage for other characteristics over these hybrids will make it an important addition for most of the areas where these hybrids are grown.

                                      TABLE 3                                      __________________________________________________________________________     1996 PERFORMANCE COMPARISON REPORT FOR CORN                                    1 YEAR SUMMARY OF ALL STANDARD TEST TYPES                                                           Income/                                                                            Pop Stand                                                                             Roots                                                                             Test                                        Brand      Product                                                                            Yield                                                                             Moist                                                                             Acre                                                                               K/Acre                                                                             (%)                                                                               (%)                                                                               Wt                                          __________________________________________________________________________     PIONEER    35R57                                                                              160.6                                                                             24.6                                                                              452.66                                                                             29.4                                                                               95 95 52.4                                        PIONEER    3578                                                                               156.6                                                                             25.1                                                                              440.33                                                                             28.2                                                                               92 97 50.8                                        Advantage      4.0                                                                               0.5                                                                               12.33                                                                              1.2 3  -2 1.6                                         Number of Comparisons                                                                         31 31 31  27  24 18 31                                          Percent Wins   80 58 74  59  54 27 87                                          Probability of Difference                                                                     87 84 90  97  79 48 99                                          PIONEER    35R57                                                                              159.3                                                                             25.6                                                                              445.54                                                                             29.2                                                                               92 97 52.5                                        PIONEER    3531                                                                               154.7                                                                             24.6                                                                              435.78                                                                             27.6                                                                               90 93 51.8                                        Advantage      4.6                                                                               -1.0                                                                              9.76                                                                               1.6 2  4  0.7                                         Number of Comparisons                                                                         97 97 97  65  55 45 97                                          Percent Wins   70 21 60  72  52 46 64                                          Probability of Difference                                                                     99 99 98  99  84 95 99                                          PIONEER    35R57                                                                              166.0                                                                             25.1                                                                              466.35                                                                             28.7                                                                               91 96 52.8                                        PIONEER    3547                                                                               160.7                                                                             25.6                                                                              450.39                                                                             28.9                                                                               89 96 54.1                                        Advantage      5.3                                                                               0.5                                                                               15.96                                                                              -0.2                                                                               2  0  -1.3                                        Number of Comparisons                                                                         113                                                                               113                                                                               113 81  70 57 112                                         Percent Wins   67 64 69  41  41 24 6                                           Probability of Difference                                                                     99 99 99  56  91 20 99                                          PIONEER    35R57                                                                              164.4                                                                             23.4                                                                              467.48                                                                             26.9                                                                               93 98 54.3                                        PIONEER    3563                                                                               159.5                                                                             22.4                                                                              456.77                                                                             26.9                                                                               92 98 55.1                                        Advantage      4.9                                                                               -1.0                                                                              10.71                                                                              0.0 1  0  -0.8                                        Number of Comparisons                                                                         458                                                                               458                                                                               458 267 188                                                                               149                                                                               419                                         Percent Wins   68 26 65  41  40 13 14                                          Probability of Difference                                                                     99 99 99  7   89 29 99                                          PIONEER    35R57                                                                              163.8                                                                             24.0                                                                              463.59                                                                             27.7                                                                               92 97 53.7                                        WEIGHTED AVG   158.9                                                                             23.4                                                                              452.10                                                                             27.4                                                                               91 97 54.2                                        Advantage      4.9                                                                               -0.6                                                                              11.49                                                                              0.3 1  0  -0.5                                        Number of Comparisons                                                                         699                                                                               699                                                                               699 440 337                                                                               269                                                                               659                                         Percent Wins   68 33 65  47  43 22 23                                          Probability of Difference                                                                     99 99 99  96  99 48 99                                          __________________________________________________________________________      NOTE: The probability values are useful in analyzing if there is a "real"      difference in the genetic potential of the products involved. High values      are desirable, with 95% considered significant for real differences.     

Comparison of Key Characteristics for Hybrid 35R57

Characteristics of Pioneer Hybrid 35R57 are compared to Pioneer Hybrids 3531, 3547, 3563, and 3578 in Table 4. The values given for most traits are on a 1-9 basis. In these cases 9 would be outstanding, while 1 would be poor for the given characteristics. Table 4 shows that hybrid 35R57 produces excellent yield, better than all of the hybrids compared. Hybrid 35R57 has better Brittle Snap resistance than all hybrids compared and good drought tolerance when compared to other hybrids. Hybrid 35R57's excellent yield combined with its other favorable agronomic characteristics should make it an important hybrid to its area of adaptation.

                                      TABLE 4                                      __________________________________________________________________________     Hybrid Patent Comparisons-Characteristics                                      Pioneer Hybrid 35R57 vs. Pioneer Hybrids 3531, 3547, 3563 and                  __________________________________________________________________________     3578                                                                                    SILK                                                                               PHY GDU  GDU                                                      VARIETY                                                                             CRM CRM CRM SILK PHY  YLD                                                                               H/POP                                                                              L/POP                                                                              D/D                                                                               S/L                                                                               R/L                                __________________________________________________________________________     35R57                                                                               104 105 106 1310 2550 9  9   8   6  6  5                                  3531 105 103 103 1290 2470 8  8   8   7  5  4                                  3547 105 104 102 1300 2450 8  8   8   7  5  6                                  3563 103 106 106 1320 2550 8  8   7   6  6  6                                  3578 104 102 104 1270 2500 8  8   8   5  7  6                                       STA     TST      PLT  EAR    BRT HSK                                                                               GLF                                                                               NLF                                VARIETY                                                                             GRN D/T WT  E/G  HT   HT D/E STK CV SPT                                                                               BLT                                __________________________________________________________________________     35R57                                                                               5   8   6   4    6    5  5   7   6  3  6                                  3531 4   7   5   5    6    6  5   5   4  4  4                                  3547 4   8   8   6    5    5  6   4      2  4                                  3563 6   7   8   4    7    4  7   5   7  3  6                                  3578 7   5   4   5    6    6  4   3      4  6                                       GOS ANT HD  GIB  EYE  ECB                                                                               ECB                                              VARIETY                                                                             WLT ROT SMT ERS  SPT  1LF                                                                               2SC                                              __________________________________________________________________________     35R57                                                                               7   3   3   4    6    4  3                                                3531 7   5   8   5    5    6  4                                                3547 8   5   7   7    4    6  5                                                3563 8   5   8   4    6    4  5                                                3578 8   4   9   6    6    5  4                                                __________________________________________________________________________

INDUSTRIAL APPLICABILITY

This invention includes hybrid maize seed of 35R57 and the hybrid maize plant produced therefrom. The foregoing was set forth by way of example and is not intended to limit the scope of the invention.

As used herein, the term plant includes plant cells, plant protoplasts, plant cell tissue cultures from which maize plants can be regenerated, plant calli, plant clumps, and plant cells that are intact in plants, or parts of plants, such as embryos, pollen, ovules, flowers, kernels, ears, cobs, leaves, seeds, husks, stalks, roots, root tips, anthers, silk and the like.

Duncan, Williams, Zehr, and Widholm, Planta, (1985) 165:322-332 reflects that 97% of the plants cultured which produced callus were capable of plant regeneration. Subsequent experiments with both inbreds and hybrids produced 91% regenerable callus which produced plants. In a further study in 1988, Songstad, Duncan & Widholm in Plant Cell Reports (1988), 7:262-265 reports several media additions which enhance regenerability of callus of two inbred lines. Other published reports also indicated that "nontraditional" tissues are capable of producing somatic embryogenesis and plant regeneration. K. P. Rao, et al., Maize Genetics Cooperation Newsletter, 60:64-65 (1986), refers to somatic embryogenesis from glume callus cultures and B. V. Conger, et al., Plant Cell Reports, 6:345-347 (1987) indicates somatic embryogenesis from the tissue cultures of maize leaf segments. Thus, it is clear from the literature that the state of the art is such that these methods of obtaining plants are, and were, "conventional" in the sense that they are routinely used and have a very high rate of success.

Tissue culture of maize is described in European Patent Application, publication 160,390, incorporated herein by reference. Maize tissue culture procedures are also described in Green and Rhodes, "Plant Regeneration in Tissue Culture of Maize," Maize for Biological Research (Plant Molecular Biology Association, Charlottesville, Va. 1982, at 367-372) and in Duncan, et al., "The Production of Callus Capable of Plant Regeneration from Immature Embryos of Numerous Zea Mays Geneotypes," 165 Planta 322-332 (1985). Thus, another aspect of this invention is to provide cells which upon growth and differentiation produce maize plants having the genotype of 35R57.

Maize is used as human food, livestock feed, and as raw material in industry. The food uses of maize, in addition to human consumption of maize kernels, include both products of dry- and wet-milling industries.

Maize, including both grain and non-grain portions of the plant, is also used extensively as livestock feed, primarily for beef cattle, dairy cattle, hogs, and poultry.

Industrial uses of maize include production of ethanol, maize starch in the wet-milling industry and maize flour in the dry-milling industry. The industrial applications of maize starch and flour are based on functional properties, such as viscosity, film formation, adhesive properties, and ability to suspend particles. The maize starch and flour have application in the paper and textile industries. Other industrial uses include applications in adhesives, building materials, foundry binders, laundry starches, explosives, oil-well muds, and other mining applications.

Plant parts other than the grain of maize are also used in industry. Stalks and husks are made into paper and wallboard and cobs are used for fuel and to make charcoal.

The seed of the hybrid maize plant and various parts of the hybrid maize plant can be utilized for human food, livestock feed, and as a raw material in industry.

Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity and understanding, it will be obvious that certain changes and modifications may be practiced within the scope of the invention, as limited only by the scope of the appended claims.

Applicants have made a deposit of at 2500 seeds of Hybrid Maize Line 35R57 with the American Type Culture Collection (ATCC), Rockville, Md. 20852 USA, ATCC Deposit No. 209597. The seeds deposited with the ATCC on Jan. 27, 1998 were taken from the deposit maintained by Pioneer Hi-Bred International, Inc., 700 Capital Square, 400 Locust Street, Des Moines, Iowa 50309-2340 since prior to the filing date of this application. This deposit of the Hybrid Maize Line 35RS7 will be maintained in the ATCC depository, which is a public depository, for a period of 30 years, or 5 years after the most recent request, or for the enforceable life of the patent, whichever is longer, and will be replaced if it becomes nonviable during that period. Additionally, Applicants have satisfied all the requirements of 37 C.F.R. §§1.801-1.809, including providing an indication of the viability of the sample. Applicants impose no restrictions on the availability of the deposited material from the ATCC; however, Applicants have no authority to waive any restrictions imposed by law on the transfer of biological material or its transportation in commerce. Applicants do not waive any infringement of their rights granted under this patent. 

What is claimed is:
 1. Hybrid maize seed designated 35R57, representative seed of said hybrid 35R57 having been deposited under ATCC accession number
 209597. 2. A maize plant, or its parts, produced by the seed of claim
 1. 3. Pollen of the plant of claim
 2. 4. An ovule of the plant of claim
 2. 5. A tissue culture of regenerable cells of a hybrid maize plant 35R57, representative seed of said hybrid maize plant 35R57 having been deposited under ATCC accession number 209597, wherein the tissue regenerates plants capable of expressing all the morphological and physiological characteristics of said hybrid maize plant 35R57.
 6. A tissue culture according to claim 5, the cells or protoplasts being of a tissue selected from the group consisting of leaves, pollen, embryos, roots, root tips, anthers, silks, flowers, kernels, ears, cobs, husks, and stalks.
 7. A maize plant, or its parts, regenerated from the tissue culture of claim 5 and capable of expressing all the morphological and physiological characteristics of hybrid maize plant 35R57, representative seed having been deposited under ATCC accession number
 209597. 